Angular vibration means sinusoidal sinusoidal angular motion having a repeated amplitude and period. As a sensor for measuring angular vibration, angular accelerometers, angular rate sensors, angular encoder for directly measuring an angular displacement, or the like, have been used.
These angular vibration sensors need to define electrical sensitivity, which is defined by a ratio of an electrical output signal to unit angular vibration.
A process of measuring electrical sensitivity of sensors for angular vibration is referred to as correction of a vibration sensor. A need exists for a need an apparatus for generating angular vibration so as to correct the sensitivity of the angular vibration sensor. The apparatus generating the angular vibration is referred to as an rotational vibration exciter.
The rotational vibration exciter is divided into a rotational shaft, a mechanical device part supporting the rotational shaft, and an electromagnetic part generating Lorentz force. The electromagnetic part generating the Lorentz force is configured to a moving coil flowing external supplying current and a magnetic generating unit generating magnetic field in a direction orthogonal to the moving coil.
FIG. 1 is an electromagnetic configuration diagram for generating torque of a general rotational vibration exciter, which generates magnetic field in a direction orthogonal to the moving coil by a permanent magnet 100 mounted under a moving coil by supplying current i to the moving coil 20 mounted on the permanent magnet 10, thereby generating torque to the moving coil.
FIG. 2 is a diagram showing the moving coil manufactured according to the related art, which includes a rotational non-conducting plate 30, coils 40 applying current in a radial direction of the rotational non-conducting plate 30, wires each connecting the coils 40, and a current supply wire 60 applying current from the outside to the coils 40.
However, according to a method for manufacturing a moving coil according to the related art, a coil having the same size needs to be manually manufactured so as to manufacture a loop type coil. In this case, when the sizes and weights of the coils are not the same, unbalance of force occurs due to an unbalanced mass of the moving coil, which results in degrading performance of the rotational exciter.
In addition, even when the sizes and weights of the coils are manufactured to be same, the unbalanced mass may occur due to a fine position difference between the coils assembled in a radial direction.
Therefore, upon manufacturing the coils by a conventional manual labor and mounting the coils on a support plate, assembling them in the desired positions is very difficult, which results in degrading the performance and quality of the rotational vibration exciter.
Moreover, even in performing a soldering operation connecting the coils with one another and assembling the current supply wires for supplying external current to the coils, the unbalanced mass cannot be avoided.
Therefore, in order to solve the problems encountered in the related art, there is “a method for manufacturing a moving coil for an rotational vibration exciter using a method for manufacturing a multi-layer PCB (Registration No. KR10-0780915)” filed and registered as Patent by the present applicant.
The method of manufacturing a moving coil for an rotational vibration exciter using a method for manufacturing a multi-layer PCB (Registration No. KR10-0780915) is an improved method for manufacturing a moving coil for an rotational vibration exciter by using a method of manufacturing a PCB to prevent the performance and quality of the rotational vibration exciter from being degraded due to manufacturing and assembling errors through the manual labor.
Therefore, according to the method for manufacturing a moving coil for an rotational vibration exciter using a method for manufacturing a multi-layer PCB (Registration No. KR10-0780915), the method for manufacturing a multi-layer PCB enables precision manufacturing of the very uniform moving coils and controls the number of wound coils by controlling the number of PCB layers, thereby controlling the torque and the method for manufacturing a multi-layer PCB can provides precisely designed coil patterns to very uniformly maintain and manage electrical characteristic values like the resistance and inductance of the plurality of moving coils.
However, even in case of the rotational vibration exciter including the moving coil made by the “method for manufacturing a moving coil for an angular exciter using a method for manufacturing a multi-layer PCB (Registration No. KR10-0780915)”, the moving coil was connected to a thick and massive cable sufficient to supply an external sinusoidal current.
However, the cable line has twist properties affecting the angular vibration of the PCB on which the moving coil for angular vibration is formed and transfers external vibration to the PCB on which the moving coil for angular vibration is formed through the cable line, such that it is difficult to accurately control the angular vibration of the PCB on which the moving coil for angular vibration is formed.